Assessment of biochar addition to natural soil and engineered soil mixtures: effects on soil structure, plant growth, and hydrology
| Author(s) | Akpinar, Derya | |
| Date Accessioned | 2023-10-09T17:11:36Z | |
| Date Available | 2023-10-09T17:11:36Z | |
| Publication Date | 2023 | |
| SWORD Update | 2023-09-20T19:15:34Z | |
| Abstract | Bioretention systems are one example of green stormwater infrastructure that may mitigate the environmental impact of stormwater runoff. Conventional bioretention soil media (BSM), an engineered soil mixture, might be augmented with biochar to improve water retention while maintaining rapid stormwater infiltration. Biochar may improve the BSM’s structure by increasing soil aggregation, promoting water retention, and increasing stormwater infiltration while enhancing plant growth. Two representative BSMs, one with high sand content and no compost, and a second with moderate sand content and compost, were amended with a wood-derived biochar, planted with switchgrass, a common bioretention plant, and monitored for 30 weeks that included wet and dry (drought) periods. Biochar amendment increased stormwater retention and hydraulic conductivity, and these effects increased with time. Improvements in hydraulic performance were correlated with increases in media aggregation in the high sand content BSM. Here, biochar enhanced aggregation by improving organo-mineral association and fungal hyphae length. ☐ Bioretention systems must maintain plants, which is challenging because most designs require significant sand to infiltrate stormwater rapidly. The effect of the wood-derived biochar on switchgrass growth, survivability during drought, and removal of stormwater nutrients were assessed. While plant growth and survivability were optimal in the biochar-free BSM with compost, biochar amendment to the high sand content/no compost BSM resulted in plant growth and survivability that mimicked the performance of the compost-amended BSM. Nutrient removal was approximately ten times greater in the biochar-amended compost-free BSM than in the compost-amended BSM. A recalcitrant carbon-like biochar mitigates some of the harmful effects of high sand-content BSM on plants. Where nutrient pollution is a concern, replacing compost/mulch with wood biochar in BSM may be desired. ☐ Urban development results in soil compaction and conversion of pervious areas into impervious surfaces, decreasing soil infiltration and increasing stormwater runoff volume and associated pollutants. Biochar amendment to compacted roadway soils is a possible treatment option. Three roadway sites were amended with different mass fractions of wood-derived biochar to assess seasonal changes in stormwater infiltration capacity, quantified by saturated hydraulic conductivity measurements. Time-dependent changes in soil structure were correlated with biochar content, vegetation growth, penetration resistance, and stormwater infiltration. Biochar may be a sustainable stormwater management practice to reduce the volume of surface runoff by enhancing the infiltration capacity of the compacted roadway soil. | |
| Advisor | Imhoff, Paul T. | |
| Degree | Ph.D. | |
| Department | University of Delaware, Department of Civil and Environmental Engineering | |
| DOI | https://doi.org/10.58088/ry9t-6n90 | |
| Unique Identifier | 1415803050 | |
| URL | https://udspace.udel.edu/handle/19716/33449 | |
| Language | en | |
| Publisher | University of Delaware | |
| URI | https://login.udel.idm.oclc.org/login?url=https://www.proquest.com/dissertations-theses/assessment-biochar-addition-natural-soil/docview/2866690983/se-2?accountid=10457 | |
| Keywords | Biochar amendment | |
| Keywords | Saturated hydraulic conductivity | |
| Keywords | Soil compaction | |
| Keywords | Soil hydrology | |
| Keywords | Vegetation growth | |
| Keywords | Water retention | |
| Title | Assessment of biochar addition to natural soil and engineered soil mixtures: effects on soil structure, plant growth, and hydrology | |
| Type | Thesis |